Nitro amines and process for preparing them



Patented Mar. 29, 1949 UNITED STATES PATENT OFFICE,

NITRO AMINES AND PROCESS FOR PREPARING THEM Murray Senkus, Terre Haute,- Ind-., assignor to- Commercial Solvents Corporation, Terre Haute, Ind., a corporation of Maryland N Drawing. Application March 14, 1947, Serial No. 734,859

1 10 Claims.

My invention relates to new n-itroiamines and to a process for the preparation thereof. Specifically, these new compoundamay be represented by th following structural formula:

in which R representsfurfuryl or tetrahydrofurfuryl, R represents hydrogen, alkyl, aralkyl.

or cycloalkyl and R and R represent alkyl groups.- w

As examples of nitro amines coming within the scope of the above formula theremay be mentioned the following: N-(Z-nitroisobutyl)-cyclo-' hexylfurfurylamine, N- (2-nitroisobutyl) -isopro'- pyltetrahydrofurfurylamine, N-(2-nitroisobuty1) cyclohexyltetrahydrofurfurylamine, N-(2-nitroisobutyl) -isopropy1furfurylamine, N- (2-nitroisobutyl) -tetrahydrofurfurylamine, N- (Z-nitroisobutyl) -furfurylamine, and N- (Z-nitroisobutyl) benzylfurfurylamine. v I

This application visa continuation-impart (of my co-pending application, Serial No. 579,895 filed February-26,1945. w I

. Prior investigators in this field have found that primary nitroparafiins would react with N-(hydroxymethyl) dialkylamines; however, they also arrived at the conclusion, while making the aforesaid discovery, that N-(hydroXymethyDrnonoalkylamines wouldnot-reactwithprimary nitroparafiins, and that secondary nitroparafiins would neither react with N,-hydroxymethyl mononor dialkylamines. underany of the experimental conditions which they had found to be effective in condensing a primary nitroparaffinwith N- (hydroxymethyl)dialkylamines. Previous Workers were of the opinion, in view of their own experimental results that neither primary nor secondary nitroparafiins would react with condensation products derivablefrom formaldehyde and ammonia, formaldehyde and primaryalkylamines. formaldehyde andaniline; formaldehyde and diphenylamine, formaldehyde and N-methylaniline, and numerous other products of similar structure prepared from-higher molecular weight a1dehydes;a -nd-primary or secondary amines.

Contrary to that which would normally be 'expected in view; of theabove prior :art findings, however,-I havediscovered-that nitro amines of thetype described may be prepared by reacting formaldehyde with a primaryor-secondary amine in which one of the--N- substituens-is-ahetero: clipes pu a ached; o the amino nitro en through a CH2 group to form the corresponding N-(hydroxymethyl) -mono-, or diamine,- which is in turn reacted with an equimolecular amount of a secondary nitroparaffin toproduce anitro amine of the type represented by the generic 5 formula given above.

A modification of the above procedure may frequently be employed to advantage, and consists of reacting the desired amine with a suitable Wnitro alcohol. A solvent may be used if desired,

but in general it will be found that a homogeneous solution .can be obtained by agitating the mixture of amine and nitro alcohol. The products, pro ducedhbyrthis process, are identical with those --synthesized by the. first mentioned method; however, the mechanismoi the reaction in its initial stages is materially diiferentfrorn that involved in the first procedure,

-.alcohols, When in the presence of a. substance -appreciablylbasie in characterjdecompose into formaldehyde and the nitroparafiin from which they were derived, and in instances where the basic material happens to be a primary or sec- ,ondary amine, the liberated formaldehyde reacts therewith to form a N-(hydroxymethyl) amine compound which: then reacts withthe nitro" parafifin, produced bythe decomposition of the nitro alcohol, in the same manner as'described in tithe first procedure. The courseof the reaction involved may be readily illustrated by the follow ing series of equations:

secondary amino starting materials are different from those used In this connection, it has been observed that primary nitro From. an examination of the aboveseries of equations, itlwill beevident that although the l in the process first described, both procedures may be considered equivalents of one another, since the compounds employed as starting materials in the first process are produced as intermediates in the second, after which said intermediates react in a manner identical with the mechanism involved in the reaction forming the basis of the first mentioned method. Therefore, it is to be specifically understood that the appended process claims include both methods.

The preparation of these nitro amines by either of the above-mentioned methods, is preferably effected at temperatures of from about 25-30 C. Temperatures above this range may be used, but in doing so care should be exercised to avoid temperatures which cause the formaldehyde to be volatilized from the reaction mixture. In some cases it may be desirable to carry out the reaction in a high pressure reaction vessel. Under such circumstances, substantially higher temperatures may be utilized without loss of formaldehyde, and decomposition of the reactants, or the reaction products.

The amines which may be employed in preparing these new compositions of matter are represented by the formula:

wherein R represents furfuryl or tetrahydrofurfuryl and R represents hydrogen, alkyl, aralkyl or cycloalkyl.

As examples of such amines, there may be mentioned furfurylamine, tetrahydrofurfurylam ne, cyclohexylfurfurylamine, cyclohexyltetrahydrofurfurylamine. isopropylfurfurylamine, isopropyltetrahydrofurfurylamine, and benzylfurfurylamine.

Nitroparafilns that are operative in my process may be represented by the following formula:

s rid-R N02 wherein R and R represent alkyl groups.

Nitroparaffins typical of this class are 2-nitrobutane, 2-nitropropane, 2-nitropentane, and the like.

In reactions wherein nitro alcohols are employed instead of a nitroparaflin and formaldehyde, the following are examples of typical nitro alcohols which may be utilized: 2-nitro-2- methyl-l-propanol, 2-nitro-2-methyl-l-butanol, 2-nitro-2-ethyl-l-butanol, and the like.

The examples which follow are illustrative of the various types of nitro amines that come within the scope of the present invention. The examples are likewise illustrative of the procedures by which said products may be synthesized. It is to be specifically understood, however, that the following examples in no way limit the scope of my invention with respect to either the product or the process, since I have found that the reaction involved is very general in nature, and will occur, under the conditions described when reacting substantially any secondary nitroparafiln with a primary or secondary amine of the various types enumerated above.

Example I A mixture which consisted of 180 g. (1 mole) of cyclohexylfurfurylamine, 120 g. (1.01 mole) of 2-nitro-2-methyl-1-propanol and 400 ml. of toluene was refluxed in. a flask connected to a moisture trap which was connected to a condenser. After 15 ml. of water had separated in the trap the mixture was dissolved in 700 ml. of petroleum ether and the solution was washed with four 1000-ml. portions of water. The petroleum ether was removed by distillation at atmospheric pressure and the toluene at mm. The distillation was then continued at 0.1 mm. This distillation yielded 18 g. of liquid, boiling range 25-109", 10 g. liquid, boiling range 109- 153 at 0.1 mm. and 195 g. of product which distilled at 153-155 at 0.1 mm. There was also 10 g. of residue.

The main cut (195 g.) is N-(Z-m'troisobu-tYD- cyclohexylfurfurylamine. Anal. calcd. for C15H24N2032 N, 10.00. Found: N, 10.08.

dig 1.0775, n? 1.5010

Example II A mixture which consisted of 143 g. (1 mole) of isopropyltetrahydrofurfurylamine, 120 g. (1.01 mole) of 2-nitro-2-methyl-l-propanol and 200 ml. of toluene was refluxed in a flask which was connected to a moisture trap and a con-denser. After 18.5 ml. of water had separated in the trap, the mixture was dissolved in 500 ml. of petroleum ether and the solution was wash-ed with three one-liter portions of water. The washed solution was distilled at atmospheric pressure to remove the petroleum ether and then at 76 mm. to remove the toluene. Further distillation yielded 14 g. of product, boiling range 26-104 at 0.1 mm. and 190 g. of product, B. P. 106-108 at 0.1 mm.

35 There was 10 g. residue.

The main cut g.) is N-(2-nitroisobutyD- isopropyltetrahydrofurfurylamine.

Anal. calcd. for C12H24N2O32 N, 11.47. Found: N, 11.94.

. n35 1.4684, dig 1.0327

Example III One mole of furfurylamine and one mole of 2- nitro-Z-methyl-l-propanol were placed in a glassstoppered reaction vessel and the mixture was shaken until it had become homogeneous. The mixture was allowed to stand at about 30 C. Water began to separate after about 10 hours. When the separation of water was substantially complete the crude product, N-(2-nitroisobutyl) furfurylamine. was separated from the lower aqueous layer and was fractionated. Fractional distillation resulted in 87 parts of product corresponding to a conversion of 44%. The product had a nitrogen content of 14.24% as compared to a calculated value of 14.12%, a boiling point of 97-98 C. at 0.6 mm. and

nf, of 1.4850 and dig of 1.1191

Example IV lag? The mixture was allowed to stand at a t-emcee:

value of13'.85%, a' boilin'g point of'IOl" Caat 0i5' mm. and

n'5.of 1.4650-and dggof 1L0729 Example V One mole (101 parts) of tetra'hydrofurfurylamine Was placed in a reaction vessel fitted with a stirrer, thermometer, and dropping funnel, then 75 parts of 35% aqueous formaldehyde were added to the amine during agitation. The mixture was externally cooled and the temperature maintained below 50 0., then 90 parts of Z-nitropropane were added to the reaction mixture and the mixture stirred for /2 hour while 500 lpartsof ethyl ether were added during. stirring. Two. layers separatedand the non-aqueous layer was separated and distilled. Distillation resulted in 104 parts of N-(2-n troisobutyl)tetrahydrofurfurylamine corresponding to a conversion of 75%. The product had a boiling point of 105 C, at 0.7

The nitro amines of my invention are in general either colorless liquids or white waxy solids. The low-molecular-weight nitro amines possess characteristic pungent odors, whereas the highmolecular-weight nitro amines are relatively odorless. The nitro amines are soluble in ether, methanol, and benzene, but are insoluble in water.

Some of the nitro amines of my invention have been found to be useful as toxicants in insect sprays. They are likewise useful as intermediates in the preparation of numerous organic compounds. Other uses of these products will readily occur to those skilled in the art.

Now having described my invention, what I claim is:

1. In the preparation of nitro amines of the formula wherein R represents a member selected from the group consisting of iurfuryl and tetrahydrofurfuryl, R is a member selected from the group consisting of hydrogen, alkyl, aralkyl or cycloalkyl and R and R represent alkyl groups, the process which comprises mixing and reacting formaldehyde and an amine having the formula N-H R2 wherein R represents a member selected fr om the group consisting of furfuryl or tetrahydrofurfuryl, R is a member selected from the group consisting of hydrogen, alkyl, aralkyl or cycloalkyl, and a nitroalkane having the formula wherein R and R represent alkyl groups, under conditions preventing any substantial loss of formaldehyde from the reaction mixture, and recovering the resulting nitroamine from the reaction mixture.

2. In the preparation of nitro amines of the formula R l lo:

wherein R 'rep'resentsiamember selectedfr'omrth'e;

group consisting of furiuryl, andtetrahydrofurfury-l, R is: a member: selected from thegroup consisting of hydrogen, alkyl, cycloalkyl and ara'lkyl, and R and Rfirepresent alkyl groups,

the p'rocesswhich' comprises mixingwi'th formaldehyde at temperature above aboutv 25 0., an aminehavingthe formula NH R2- wherein R represents a member selected from the group consisting of furfuryl, and tetrahydrofurfuryl and It represents a member selected from the group consisting of hydrogen, alkyl, cycloalkyl an'd aralkyL and a nitroalkane of the formula:

In H-o-R wherein R and R represent alkyl groups, under conditions preventing any substantial loss of formaldehyde from the reaction mixture, and recovering the resulting nitroamine from the reaction mixture.

3. In the preparation of nitro amines of the formula wherein R represents a member selected from the group consisting of furfuryl and tetrahydrofurfury], R is a member selected from the group consisting of hydrogen, alkyl, cycloalkyl and aralkyl, and R. and R represent alkyl groups, the process which comprises mixing at temperatures above about 25 C. an amine having the formula N-H R2 wherein R represents a member selected from the group consisting of furfuryl and tetrahydrofurfuryl and R represents a member selected from the group consisting of hydrogen, alkyl, cycloalkyl and aralkyl, and a nitro alcohol of the formula R3 noom-t-ru wherein R and R represent alkyl groups, under conditions preventing any substantial loss of formaldehyde from the reaction mixture, and re covering the resulting nitroamine from the reaction mixture.

4. In the preparation of N-(2-nitroisobutyD- cyclohexylfurfurylamine, the process which comprises mixing and reacting cyclohexylfurfurylamine, formaldehyde, and 2-nitropropane, under conditions preventing any substantial loss of formaldehyde from the reaction mixture, and recovering the resulting N-(2-nitroisobutyl)- cyclohexylfurfurylamine from the reaction mixture.

5. In the preparation of N-(Z-nitroisobutyD- isopropyltetrahydrofurfurylamlne, the process which comprises mixing and reacting isopropyltetrahydrofurfurylamine, formaldehyde, and 2- nitropropane, under conditions preventing any substantial loss of formaldehyde from the reaction mixture, and recovering the resulting N-(2- 7 1 nitroisobutyl) -isopropyltetrahydrofurfurylamine alkyl and R and Rrepresenta-lkyl groups. from the reaction mixture. i 8. N-(2-nitroisobuty1)cyclohexyfurfurylaminet 6. In the preparation of N-(Z-nitroisobutyi) 9. N-(2-nitroisobutyl)furfurylamine. furfurylamine, the process which comprises mix- 10. N (2 nitroisobutyl)isopropyltetrahydroing and reacting furfurylamine, formaldehyde, furfurylamine. and 2-nitropropane, under conditions preventing MURRAY SENKUS. any substantial loss of formaldehyde from the reaction mixture, and recovering the resulting REFERENCES CITED N'( 2'mt1sbuty1)furfurylamme from the The following references are of record in the actlon mlxturefile of this patent:

7. A composition of matter including nitro amines of the general type UNITED STATES PATENTS R1 N02 Number Name Date 2,206,885 Dickey et a1 July 9, 1940 l R: I 15 2,253,082 McNally et a1 Aug. 9, 1941 1 2,292,212 Dickey et a1 Aug. 4, 1942 1 wherein R represents a member selected from the group consisting of furfuryl and tetrahydro OTHER REFERENCES furfuryl, R is a member selected from the group Chemical Ab., 1938, page 494. consisting of hydrogen, alkyl, aralkyl and cyclo- Certificate of Correction j Patent No. 2,465,958

March 29, 1949 MURRAY SENKUS It is hereby certified that errors appear in numbered patent requiring corrccti the printed specification of the above on as follows: nos 5 to 8, for that p0 be read W1th these correc e record of the case in the Pa tions therein that tent Oflice. ecember, A. D. 1949. 

